Peptide deformylase inhibitors

ABSTRACT

PDF inhibitors and novel methods for their use are provided.

FIELD OF THE INVENTION

[0001] The present invention relates to the use of novel anti-bacterialcompounds, and pharmaceutical compositions containing these compounds aspeptide deformylase inhibitors.

BACKGROUND OF THE INVENTION

[0002] Bacterial initiator methionyl tRNA is modified by methionyl tRNAformyltransferase (FMT) to produce formyl-methionyl tRNA. The formylmethionine (f-met) is then incorporated at the N-termini of newlysynthesized polypeptides. Polypeptide deformylase (PDP or Def) thendeformylates primary translation products to produce N-methionylpolypeptides. Most intracellular proteins are further processed bymethionine amino peptidase (MAP) to yield the mature peptide and freemethionine, which is recycled. PDF and MAP are both essential forbacterial growth, and PDF is required for MAP activity. This series ofreactions is referred to as the methionine cycle (FIG. 1)

[0003] To date, polypeptide deformylase homologous genes have been foundin bacteria, in chloroplast-containing plants, in mice and in humans.The plant proteins are nuclear encoded but appear to carry a chloroplastlocalisation signal. This is consistent with the observation thatchloroplast RNA and protein synthesis processes are highly similar tothose of eubacteria. While there is limited information on proteinexpression of mammalian PDF gene homologs (Bayer Aktiengesellschaft,Pat. WO2001/42431), no functional role for such proteins has beendemonstrated to date (Meinnel, T., Parasitology Today 16(4), 165-168,2000).

[0004] Polypeptide deformylase is found in all eubacteria for which highcoverage genomic sequence information is available. Sequence diversityamong PDF homologs is high, with as little as 20% identity betweendistantly related sequences. However, conservation around the activesite is very high, with several completely conserved residues, includingone cyteine and two histidines which are required to coordinate theactive site metal (Meinnel, T. et al, 1997, Journal of MolecularBiology, 267, 749-761).

[0005] PDF is recoginzed to be an attractive anti-bacterial target, asthis enzyme has been demonstrated to be essential for bacterial growthin vitro (Mazel, D. et al, EMBO J. 13 (4), 914-923, 1994), is notbelieved to be involved in eukaryotic protein synthesis (Rajagopalan etal, J. Am. Chem. Soc. 119, 12418-12419, 1997), and is universallyconserved in prokaryotes (Kozak, M. Microbiol. Rev. 47, 1-45, 1983).Therefore PDF inhibitors can potentially serve as broad spectrumanti-bacterial agents.

SUMMARY OF THE INVENTION

[0006] The present invention involves novel anti-bacterial compoundsrepresented by Formula (I) hereinbelow and their use as PDF inhibitors.

[0007] The present invention further provides methods for inhibiting PDFin an animal, including humans, which comprises administering to asubject in need of treatment an effective amount of a compound ofFormula (I) as indicated hereinbelow.

DETAILED DESCRIPTION OF THE INVENTION

[0008] The compounds useful in the present methods are selected fromFormula (I) hereinbelow:

[0009] wherein:

[0010] R1 is selected from the group consisting of C₁₋₆alkyl,—C₁₋₂alkylAr, and Ar;

[0011] R2 is selected from the group consisting of hydrogen, C₁₋₆alkyl,—(CH₂)_(m)OH, —(CH₂)_(n)Ar′,

[0012] —(CH₂)_(n)Het, -Ar′, —SO₂R3, —C(O)R3, —C(O)NHR3, —C(O)OR3,—CH(R4)CONR5R6, and

[0013] —CH(R4)CO₂R7;

[0014] R3 is selected from the group consisting of C₁₋₆alkyl,—C₁₋₂alkylAr′, and Ar′;

[0015] R4 is hydrogen, or C₁₋₆alkyl;

[0016] R5 and R6 are independently selected from the group consisting ofhydrogen, C₁₋₆alkyl, C₁₋₂alkylAr′, and Ar′; and R5, R6 together form afive or six membered cycloalkyl ring which is optionallymono-substituted by —CH₂OR7;

[0017] R7 is selected from the group consisting of hydrogen, andC₁₋₃alkyl;

[0018] Ar is selected from the group consisting of phenyl, furyl, andthienyl, all of which may be optionally substituted by one or more Z₁groups;

[0019] Ar′ is selected from the group consisting of phenyl, naphthyl,furyl, pyridyl, thienyl, thiazolyl, isothiazolyl, pyrazolyl, triazolyl,tetrazolyl, imidazolyl, imidazolidinyl, benzofuranyl, indolyl,thiazolidinyl, isoxazolyl, oxadiazolyl, thiadiazolyl, morpholinyl,piperidinyl, piperazinyl, pyrrolyl, and pyrimidyl, all of which may beoptionally substituted by one or more Z₂ groups;

[0020] Het is selected from the group consisting of tetrahydrofuranyland piperidinyl;

[0021] Z₁ is independently selected from the group consisting ofC₁₋₃alkyl, —CN, F, Cl, Br, and I;

[0022] Z₂ is independently selected from the group consisting ofC₁₋₆alkyl, —OR2,

[0023] —(CH₂)_(n)CO₂R4, —C(O)NR5R6, —CN, —(CH₂)_(n)OH, —NO₂, F, Cl, Br,I, —NR5R6, and

[0024] —NHC(O)R1;

[0025] m is 2 to 5; and

[0026] n is 0 to 5.

[0027] As used herein, “alkyl” refers to a hydrocarbon group joinedtogether by single carbon-carbon bonds. The alkyl hydrocarbon group maybe linear, branched or cyclic.

[0028] Preferred compounds useful in the present invention are selectedfrom the group consisting of:

[0029]2-[4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide;

[0030]2-[(3R,4R)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide;and

[0031]2-[(3S,4S)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide.

[0032] Also included in the present invention are pharmaceuticallyacceptable salts and complexes, such as the hydrochloride, bydrobromideand trifluoroacetate salts, and the sodium, potassium and magnesiumsalts. The compounds of the present invention may contain one or moreasymmetric carbon atoms and may exist in racemic and optically activeforms. All of these compounds and diastereomers are contemplated to bewithin the scope of the present invention.

[0033] The compounds and processes of the present invention will bebetter understood in connection with the following synthetic schemes,which are merely illustrative of the methods by which the compounds ofthe invention may be prepared and are not intended to limit the scope ofthe invention as defined in the appended claims.

[0034] The present invention provides compounds of formula (I):

[0035] that can be prepared by a process consisting of:

[0036] treating an unsaturated lactone of Formula (2)

[0037] with, e.g., a Grignard reagent R1MgX in the presence of catalyticammount of a copper salt, such as copper (I) bromide, HMPA andchlorotrimethylsilane at an appropriate temperature, to afford a lactoneof Formula (3).

[0038] Treatment of a lactone of Formula (3) with bromine in thepresence of a catalytic amount of phosphorous tribromide anddimethylformamide, followed by treatment with thionyl chloride, gives acompound of Formula (4).

[0039] Reaction of an acid chloride of Formula (4) with an amine ofFormula (5)

R2—NH₂  (5)

[0040] in a suitable solvent, such as chloroform, in the presence of abase, such as sodium hydroxide, followed by cyclization with, e.g.,sodium hydride in refluxing toluene, affords a lactam of Formula (6).

[0041] Reacting an α-bromo-lactam of Formula (6) with, e.g., the sodiumsalt of t-butyl methyl malonate in a suitable solvent, such asdimethylformamide, followed by decarboxylation in refluxing toluene inthe presence of catalytic amount of p-toluenesulfonic acid, affords acompound of Formula (7).

[0042] Removal of the protecting group (if any) in R1 and/or R2,followed by treatment with 50% hydroxylamine in water in a suitablesolvent, such as dioxane, affords a racemic compound of Formula (I).

[0043] A bromo-lactam of Formula (6) can be converted to a des-bromocompound of Formula (8) using an appropriate reducing agent, such assodium borohydride, in an appropriate solvent.

[0044] Alternatively, an intermediate of Formula (8) can be preparedstarting from an aldehyde of Formula (9)

R1CHO  (9)

[0045] that is reacted with Ph₃P═CHCO₂Et in a solvent, such astetrahydrofuran, to give an α,β-unsaturated ester of Formula (10).

[0046] Treatment of a compound of Formula (10) with nitromethane inpresence of Triton B leads to a Michael addition product of Formula(11).

[0047] Reduction of the nitro group in a compound of Formula (11) underhydrogenation conditions and intramolecular cyclization, at appropriatetemperature in an appropriate solvent, such as toluene, affords a lactamof Formula (8) wherein R2═H, which can be converted to a compound ofFormula (8) wherein R2 is other than H through an alkylation reaction.

[0048] The lactam nitrogen of a compound of Formula (8) wherein R2═H canbe protected using an appropriate protecting group, such as a Boc group,under standard conditions to give a versatile intermediate of Formula(12).

[0049] Treatment of an enolate generated from a lactam of Formula (8)with an appropriate alkylating agent, such as ethyl bromoacetate, in anappropriate solvent, such as dry tetrahydrofuran, affords an ester ofFormula (13).

[0050] Removal of the Boc group from compounds of Formula (13) using anappropriate acid, such as trifluoroacetic acid, gives a compound ofFormula (14).

[0051] A lactam of Formula (14) is then readily converted to the targetcompound of Formula (I) by treatment with an alkyl halide, a sulfonylchloride, an acid chloride or an isocyanate followed by treatment with a50% hydroxyamine solution.

[0052] An optically active compound of Formula (1) can be prepared bytreating a lactone of Formula (3) with a chiral amine, such as(S)-methylphenyl amine, in the presence of a catalyst, such as2-hydroxypyridine, in a suitable solvent, such as toluene, at reflux toafford a mixture of two diastereomers of Formula (15) and (16), whichcan be readily separated by silica gel flash column chromatography.

[0053] Intramolecular Mitsunobu reaction of a compound of Formula (15)or (16) affords a lactam of Formula (17) or (18), respectively.

[0054] Removal of the N-protecting group of lactam of a compound ofFormula (17) or (18) with sodium in liquid ammonia affords an opticallypure lactam of Formula (19) or (20), respectively.

[0055] Treatment of a lactam of Formula (19) or (20) with a compound ofFormula (21)

R2—X  (21)

[0056] in the presence of a base, such as sodium hydride ortriethylamine, in a suitable solvent, such as dimethylformamide ormethylene chloride, affords a compound of Formula (22) or (23).

[0057] Conversion of a chiral lactam of Formula (22) or (23) to thechiral target compound of Formula (I) can then be achieved usingreagents and conditions described above for transformation of a racemiccompound of Formula (8) to a racemic compound of Formula (I).

[0058] The present compounds are further exemplified by the followingExamples which are intended to be illustrative of the present inventionand not limiting in any way.

EXAMPLE 1

[0059] Preparation of2-[4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide

[0060] 1(a) 1-(5-Benzyloxypentyl)-3-bromo-4-butylpyrrolidin-2-one

[0061] A mixture of 4-butyldihydrofuran-2-one (4.26 g, 30 mmol) andphosphorous tribromide (0.052 mL, 0.55 mmol) was heated to 110° C. underargon. Bromine (1.29 mL, 25.2 mmol) was added slowly into the reactionmixture. The reaction was cooled slowly to 50° C. and dimethylformamide(0.003 mL) was added. After heating up to 90° C., thionyl chloride (2.58mL, 30 mmol) was added slowly and the reaction was continued at the sametemperature for 3h. Removal of the volatiles under reduced pressure gave9.0 g (94%) of a brown oil, presumably 2,4-dibromo-3-butylbutyrylchloride, which was directly used for the next step withoutpurification. A portion of this crude compound (2.5 g, 7.7 mmoL) wasdissolved in chloroform (10 mL) and cooled to 0° C. To this coldsolution was added 5-benzyloxypentyl amine (1.5 g, 7.7 mmol) inchloroform (10 mL). After 10 minutes, sodium hydroxide (0.34 g, 8.5mmol) in water (3 ml) was added with vigorous stirring. The reaction wascontinued at 0° C. for 1 h, the organic phase was separated and washedwith 0.5 N HCl (10 mL), water (10 mL), saturated NaHCO₃(10 mL), brine(10 mL) and dried (Na₂SO₄). After filtration, the solvent was removedunder reduced pressure. The residue was dissolved in benzene (20 mL),cooled with an ice bath and treated carefully with small portions ofsodium hydride (60% in mineral oil, 0.31 g, 7.7 mmol). After 30 minutes,the reaction mixture was poured into ice water, the organic phase wasseparated and washed with brine (10 mL), dried (Na₂SO₄). Afterfiltration and removing the solvent, the residue was purified by flashcolumn chromatography (silica gel, 1:3 EtOAc/hexanes) to afford 1.6 g(52%) of the title compound as a yellow oil: ¹H NMR (CDCl₃) δ 7.34 (m,5H), 4.53 (s, 2H), 4.32 (d, 1H), 3.65 (m, 2H), 3.48 (t, 2H), 3.29 (m,2H), 2.48 (m, 1H), 1.24-1.70 (m, 12H), 0.91 (t, 3H). MS(ES) m/e 396[M+H]⁺.

[0062] 1(b) 1-(5-Benzyloxypentyl)-4-butyl-2-oxopyrrolidin-3-yl]CeticAcid, Methyl Ester

[0063] A solution of t-butyl methyl malonate (0.69 g, 3.9 mmol) indimethylformamide (10 mL) was treated with sodium hydride (60% inmineral oil, 0.16 g, 3.9 mmol) at 60° C. for 30 minutes. After coolingto room temperature, a solution of the compound of Example 1(a) (1.2 g,3.0 mmol) in dimethylformamide (10 mL) was added dropwise. Afterstirring at room temperature overnight, the reaction mixture was dilutedwith ethyl acetate/hexanes (1:1, 100 mL) and washed with water (5×50 mL)and brine (50 mL), and dried (Na₂SO₄). After removing the solvent underthe reduced pressure, the residue was dissolved in toluene (100 mL) andp-toluenesulfonic acid monohydrate (0.2 g, 1.0 mmol) was added. Theresulting mixture was heated to reflux for 2h. After cooling to roomtemperature, the mixture was diluted with ethyl acetate (50 mL), washedwith saturated NaHCO₃ (50 mL) and brine (50 mL), and dried (Na₂So₄).After removing the solvent under the reduced pressure, the residue waspurified by flash column chromatography (silica gel, 1:4 EtOAc/hexanes)to afford 0.47 g (40%) of the title compound as a brown oil: ¹H NMR(CDCl₃) δ 7.34 (m, 5H), 4.55 (s, 2H), 3.67 (s, 3H), 3.54 (m, 3H), 3.33(m, 2H), 3.05 (m, 1H), 2.68 (m, 3H), 2.16 (m, 1H), 1.25-1.70 (m, 12H),0.93 (t, 3H). MS(ES) m/e 390 [M+H]⁺.

[0064] 1(c)2-[4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide

[0065] A solution of the compound of Example 1(b) (50 mg, 0.13 mmol) inmethanol (3 mL) was stirred under a hydrogen balloon in the presence ofpalladium on activated carbon at room temperature overnight. Thereaction mixture was filtered and concentrated to afford 37 mg (95%) ofa clear oil, presumably(+/−)-[4-butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]acetic acid,methyl ester, MS(ES) m/e 300 [M+H]⁺. This compound was dissolved indioxane (1.5 mL) and was treated with hydroxylamine in water (50%, 2 mL)at room temperature overnight. The reaction mixture was concentratedunder vacuum and purified by automated HPLC to afford 25 mg (68%) of thetitle compound as a clear glass: ¹H NMR (CD₃OD) δ 3.56 (m, 3H), 3.33 (m,2H), 3.07 (m, 1H), 2.53 (m, 2H), 2.18 (m, 1H), 2.12 (m, 2H), 1.31-1.70(m, 12H), 0.93 (t, 3H). MS(ES) m/e 301 [M+H]⁺.

EXAMPLE 2

[0066] Preparation of2-[(3R,4R)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide

[0067] 2(a) (R)-3-Hydroxymethylheptanoic acid, (S)-1-phenylethylamide

[0068] A mixture of (+/−)-4-butyldihydrofuran-2-one (3.9 g, 27.4 mmol),2-hydroxypyridine (3.1 g, 32.9 mmol) and (S)-1-phenylethyl amine (7.8mL, 60.3 mmol) in dry toluene (50 mL) was heated to reflux overnight.The reaction mixture was cooled to room temperature and diluted withethyl acetate (100 mL), washed with 1 N HCl (2×50 mL) and brine (50 mL),dried (Na₂SO₄), and concentrated. The residue was purified by flashcolumn chromatography (silica gel, 8:2 EtOAc/hexanes) to afford twocompounds as white solids. The first eluted fraction was(S)-3-hydroxymethylheptanoic acid, (S)-1-phenyl-ethylamide (2.8 g, 39%)which is used in Example 3. ¹H NMR (CDCl₃) δ 7.33 (m, 5H), 6.07 (bs,1H), 5.11 (q, 1H), 3.63 (m, 1H), 3.48 (m, 1H), 3.29 (bs, 1H), 2.29 (m,2H), 1.95 (m, 1H), 1.50 (d, 2H), 1.28 (m, 6H), 0.88 (t, 3H). MS(ES) m/e264 [M+H]⁺. The second eluted fraction was the title compound (2.6 g,36%). ¹H NMR (CDCl₃) δ 7.29 (m, 5H), 6.34 (bs, 1H), 5.09 (q, 1H), 3.64(m, 1H), 3.57 (bs, 1H), 3.48 (m, 1H), 2.28 (m, 2H), 1.93 (m, 1H), 1.48(d, 2H), 1.28 (m, 6H), 0.88 (t, 3H). MS(ES) m/e 264 [M+H]⁺.

[0069] 2(b) (R)4-Butyl-1-[(S)-1-phenylethyl]pyrrolidin-2-one

[0070] To a solution of di-t-butylazodicarboxylate (2.1 g, 9.1 mmol) intetrahydrofuran (25 mL) under argon was added tributylphosphine (2.27mL, 9.1 mmol). The mixture was stirred for 5 minutes and was addedslowly to a solution of the compound of Example 2(a) (1.84 g, 7.0 mmol)in dry THF (10 mL) at 0° C. The reaction was warmed up to roomtemperature and the reaction mixture was stirred overnight. SaturatedNaHCO₃ (100 mL) was added to the reaction mixture and the resultingmixture was extrated with CHCl₂ (2×100 mL). The combined organicextracts were dried (Na₂SO₄), filtered and concentrated. The residue waspurified by flash column chromatography (silica gel, 1:4 EtOAc/hexanes)to afford 1.4 g (82%) of the title compound as a clear oil: ¹H NMR(CDCl₃) δ 7.33 (m, 5H), 5.48 (q, 1H), 3.06 (t, 1H), 2.92 (t, 1H), 2.53(q, 1H), 2.06 (m, 2H), 1.51 (d, 3H), 1.201.46 (m, 6H), 0.88 (t, 3H).MS(ES) m/e 246 [M+H]⁺.

[0071] 2(c) (R)-4-Butylpyrrolidin-2-one

[0072] To a solution of compound of Example 2(b) (1.4 g, 5.7 mmol) indry tetrahydrofuran (10 mL) at −78° C. was condensed liquid ammonia (100mL). Freshly cut sodium (0.66 g, 28.5 mmol) was added and the resultingmixture was stirred at −78° C. for 2h. The reaction was quenched withsolid ammonium chloride. Ammonia was evaporated by warming up thereaction mixture slowly to room temperature. Water (50 mL) was added andthe mixture was extracted with ethyl acetate (3×50 mL). The combinedorganic extracts were dried (Na₂SO₄), filtered and concentrated. Theresidue was purified by flash column chromatography (silica gel, 8:2EtOAc/acetone) to afford 0.7 g (87%) of the title compound as a clearoil: [α]_(D)=+0.950 (c=0.60, CH₂Cl₂) {lit. [α]_(D)=−0.670 (c=0.60,CH₂Cl₂) for (S)-enantiomer, Meyers, A. I. and Snyder, L. 1993, J. Org.Chem. 58, 36-42};

[0073]¹H NMR (CDCl₃) δ 6.07 (bs, 1H), 3.48 (t, 1H), 3.02 (t, 1H), 2.45(m, 2H), 1.99 (m, 1H), 1.22-1.50 (m, 6H), 0.90 (t, 3H). MS(ES) m/e 142[M+H]⁺.

[0074] 2(d) (R)-1-(5-Benzyloxypentyl)-4-butylpyrrolidin-2-one

[0075] To a solution of the compound of Example 2(c) (0.42 g, 2.9 mmol)in dry dimethylformamide (10 mL) under argon was slowly added sodiumhydride (60% in mineral oil, 0.14 g, 3.5 mmol) at 0° C. After stirringat 0° C. for 30 minutes, 5-benzyloxypentyl bromide (0.9 g, 3.5 mmol) wasdropwise added. The resulting mixture was stirred at room temperatureovernight and then diluted with ethyl acetate (50 mL). The organicsolution was washed with water (4×30 mL), brine (30 mL), dried (Na₂SO₄)and concentrated. The residue was purified by flash columnchromatography (silica gel, 1:1 EtOAc/hexanes) to afford 0.73 g (95%) ofthe title compound as a clear oil: ¹H NMR (CDCl₃) δ 7.33 (m, 5H), 4.51(s, 2H), 3.45 (m, 3H), 3.27 (t, 2H), 2.99 (dd, 1H), 2.52 (dd, 1H), 2.32(m, 1H), 2.06 (m, 1H), 1.24-1.71 (m, 12H), 0.93 (t, 3H). MS(ES) m/e 318[M+H]⁺.

[0076] 2(e)[(3R,4R)-1-(5-Benzyloxypentyl)-4-butyl-2-oxopyrrolidin-3-yl]Acetic Acid,Ethyl Ester

[0077] To a 2 M solution of lithium diisopropylamide (0.47 mL, 0.94mmol) in THF (2 mL) at −78° C. under argon was slowly added a solutionof the compound of Example 2(d) (0.25 g, 0.79 mmol) in dry THBF (3 mL).After stirring at the same temperature for 1 h. Bromo ethyl acetate (0.1mL, 0.94 mmol) was dropwise added. The resulting mixture was continuedto stir for 3h and then quenched with saturated ammonium chloride (10mL). The mixture was extracted with ethyl acetate (3×10 mL), thecombined organic extracts were dried (Na₂SO₄), filtered, andconcentrated. The residue was purified by HPLC to afford 0.11 g (35%) ofthe title compound as a brown oil: ¹H NMR (CDCl₃) δ 7.35 (m, 5H), 4.51(s, 2H), 4.16 (q, 2H), 3.48 (t, 2H), 3.44 (m, 1H), 3.29(m, 2H), 2.98 (m,1H), 2.75 (m,1H), 2.52 (m, 1H), 2.08 (m, 1H), 1.31-1.72 (m, 12H), 1.29(t, 3H), 0.91 (t, 3H). MS(ES) m/e 404 [M+H]⁺.

[0078] 2(f)2-[(3R,4R)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide

[0079] Following the procedure of Example 1(c), except substituting thecompound of Example 1(b) with the compound of Example 2(e), the titlecompound was prepared (50%).

[0080]¹H NMR (CD₃OD) δ 3.56 (m, 3H), 3.32 (m, 2H), 3.07 (m, 1H), 2.54(m, 2H), 2.18 (m, 1H), 2.11 (m, 2H), 1.33-1.79 (m, 12H), 0.94 (t, 3H).MS(ES) m/e 301 [M+H]⁺.

Example 3

[0081] Preparation of2-[(3S,4S)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide

[0082] Following the procedure of Example 2(b)-2(f), except substituting(R)-3-hydroxymethylheptanoic acid (S)-1-phenylethylamide with(S)-3-hydroxymethylheptanoic acid, (S)-1-phenylethylamide, the titlecompound was prepared. It has the same ¹H NMR and MS as the compound ofExample 2(f).

[0083] With appropriate manipulation and protection of any chemicalfunctionality, synthesis of the remaining compounds of Formula (1) isaccomplished by methods analogous to those above and to those describedin the Experimental section.

[0084] In order to use a compound of the Formula (I) or apharmaceutically acceptable salt thereof for the treatment of humans andother mammals it is normally formulated in accordance with standardpharmaceutical practice as a pharmaceutical composition.

[0085] The present compounds are useful for the treatment of bacterialinfections including but not limited to respiratory tract infectionsand/or Gram positive infections.

[0086] Compounds of Formula (I) and their pharmaceutically acceptablesalts may be administered in a standard manner for antibiotics, forexample orally, parenterally, sublingually, dermally, transdermally,rectally, via inhalation or via buccal administration.

[0087] Compositions of Formula (I) and their pharmaceutically acceptablesalts which are active when given orally can be formulated as syrups,tablets, capsules, creams and lozenges. A syrup formulation willgenerally consist of a suspension or solution of the compound or salt ina liquid carrier for example, ethanol, peanut oil, olive oil, glycerineor water with a flavoring or coloring agent. Where the composition is inthe form of a tablet, any pharmaceutical carrier routinely used forpreparing solid formulations may be used. Examples of such carriersinclude magnesium stearate, terra alba, talc, gelatin, acacia, stearicacid, starch, lactose and sucrose. Where the composition is in the formof a capsule, any routine encapsulation is suitable, for example usingthe aforementioned carriers in a hard gelatin capsule shell. Where thecomposition is in the form of a soft gelatin shell capsule anypharmaceutical carrier routinely used for preparing dispersions orsuspensions may be considered, for example aqueous gums, celluloses,silicates or oils, and are incorporated in a soft gelatin capsule shell.

[0088] Typical parenteral compositions consist of a solution orsuspension of a compound or salt in a sterile aqueous or non-aqueouscarrier optionally containing a parenterally acceptable oil, for examplepolyethylene glycol, polyvinylpyrrolidone, lecithin, arachis oil orsesame oil.

[0089] Typical compositions for inhalation are in the form of asolution, suspension or emulsion that may be administered as a drypowder or in the form of an aerosol using a conventional propellant suchas dichlorodifluoromethane or trichlorofluoromethane.

[0090] A typical suppository formulation comprises a compound of Formula(I) or a pharmaceutically acceptable salt thereof which is active whenadministered in this way, with a binding and/or lubricating agent, forexample polymeric glycols, gelatins, cocoa-butter or other low meltingvegetable waxes or fats or their synthetic analogs.

[0091] Typical dermal and transdermal formulations comprise aconventional aqueous or non-aqueous vehicle, for example a cream,ointment, lotion or paste or are in the form of a medicated plaster,patch or membrane.

[0092] Preferably the composition is in unit dosage form, for example atablet, capsule or metered aerosol dose, so that the patient mayadminister a single dose.

[0093] Each dosage unit for oral administration contains suitably from0.1 mg to 500 mg/Kg, and preferably from 1 mg to 100 mg/Kg, and eachdosage unit for parenteral administration contains suitably from 0.1 mgto 100 mg/Kg, of a compound of Formula(I) or a pharmaceuticallyacceptable salt thereof calculated as the free acid. Each dosage unitfor intranasal administration contains suitably 1400 mg and preferably10 to 200 mg per person. A topical formulation contains suitably 0.01 to5.0% of a compound of Formula (I).

[0094] The daily dosage regimen for oral administration is suitablyabout 0.01 mg/Kg to 40 mg/Kg, of a compound of Formula(I) or apharmaceutically acceptable salt thereof calculated as the free acid.The daily dosage regimen for parenteral administration is suitably about0.001 mg/Kg to 40 mg/Kg, of a compound of Formula (I) or apharmaceutically acceptable salt thereof calculated as the free acid.the daily dosage regimen for intranasal administration and oralinhalation is suitably about 10 to about 500 mg/person. The activeingredient may be administered from 1 to 6 times a day, sufficient toexhibit the desired activity.

[0095] No unacceptable toxicological effects are expected when compoundsof the present invention are administered in accordance with the presentinvention.

[0096] The biological activity of the compounds of Formula (I) aredemonstrated by the following test:

[0097] Biological Assay:

[0098]S. aureus or E. coli PDF activity is measured at 25° C., using acontinuous enzyme-linked assay developed by Lazennec & Meinnel, (1997)“Formate dehydrogenase-coupled spectrophotometric assay of peptidedeformylase” Anal. Biochem. 244, pp.180-182, with minor modifications.The reaction mixture is contained in 50 uL with 50 mM potassiumphosphate buffer (pH7.6), 15 mM NAD, 0.25 U formate dehydrogenase. Thesubstrate peptide, f-Met-Ala-Ser, is included at the KM concentration.The reaction is triggered with the addition of 10 nM Def1 enzyme, andabsorbance is monitored for 20 min at 340 nm.

[0099] Antimicrobial Activity Assay

[0100] Whole-cell antimicrobial activity was determined by brothmicrodilution using the National Committee for Clinical LaboratoryStandards (NCCLS) recommended procedure, Document M7-A4, “Methods forDilution Susceptibility Tests for Bacteria that Grow Aerobically”(incorporated by reference herein). The compound was tested in serialtwo-fold dilutions ranging from 0.06 to 64 mcg/ml. A panel of 12 strainswere evaluated in the assay. This panel consisted of the followinglaboratory strains: Staphylococcus aureus Oxford, Staphylococcus aureusWCUH29, Enterococcus faecalis I, Enterococcus faecalis 7, Haemophilusinfluenzae Q1, Haemophilus influenzae NEMC1, Moraxella catarrhalis 1502,Streptococcus pneumoniae 1629, Streptococcus pneumoniae N1387,Streptococcus pneumoniae N1387, E. coli 7623 (AcrABEFD+) and E. coli 120(AcrAB−). The minimum inhibitory concentration (MIC) was determined asthe lowest concentration of compound that inhibited visible growth. Amirror reader was used to assist in determining the MIC endpoint.

[0101] All publications, including but not limited to patents and patentapplications, cited in this specification are herein incorporated byreference as if each individual publication were specifically andindividually indicated to be incorporated by reference herein as thoughfully set forth.

[0102] The above description fully discloses the invention includingpreferred embodiments thereof. Modifications and improvements of theembodiments specifically disclosed herein are within the scope of thefollowing claims. Without further elaboration, it is believed that oneskilled in the area can, using the preceding description, utilize thepresent invention to its fullest extent. Therefore the Examples hereinare to be construed as merely illustrative and not a limitation of thescope of the present invention in any way. The embodiments of theinvention in which an exclusive property or privilege is claimed aredefined as follows.

What is claimed is:
 1. A compound according to formula (1):

wherein: R1 is selected from the group consisting of C₁₋₆alkyl,—C₁₋₂alkylAr, and Ar; R2 is selected from the group consisting ofhydrogen, C₁₋₆alkyl, —(CH₂)_(m)OH, —(CH₂)_(n)Ar′, —(CH₂)_(n)Het, -Ar′,—SO₂R3, —C(O)R3, —C(O)NHR3, —C(O)OR3, —CH(R4)CONR5R6, and —CH(R4)CO₂R7;R3 is selected from the group consisting of C₁₋₆alkyl, —C₁₋₂alkylAr′,and Ar′; R4 is hydrogen, or C₁₋₆alkyl; R5 and R6 are independentlyselected from the group consisting of hydrogen, C₁₋₆alkyl,—C₁₋₂alkylAr′, and Ar′; or R5, R6 together form a five or six memberedcycloalkyl ring which is optionally mono-substituted by —CH₂OR7; R7 isselected from the group consisting of hydrogen, and C₁₋₃alkyl; Ar isselected from the group consisting of phenyl, furyl, and thienyl, all ofwhich may be optionally substituted by one or more Z₁ groups; Ar′ isselected from the group consisting of phenyl, naphthyl, furyl, pyridyl,thienyl, thiazolyl, isothiazolyl, pyrazolyl, triazolyl, tetrazolyl,imidazolyl, imidazolidinyl, benzofuranyl, indolyl, thiazolidinyl,isoxazolyl, oxadiazolyl, thiadiazolyl, morpholinyl, piperidinyl,piperazinyl, pyrrolyl, and pyrimidyl, all of which may be optionallysubstituted by one or more Z₂ groups; Het is selected from the groupconsisting of tetrahydrofuranyl and piperidinyl; Z₁ is independentlyselected from the group consisting of C₁₋₃alkyl, —CN, F, Cl, Br, and I;Z₂ is independently selected from the group consisting of C₁₋₆alkyl,—OR2, —(CH₂)_(n)CO₂R4, —C(O)NR5R6, —CN, —(CH₂)_(n)OH, —NO₂, F, Cl, Br,I, —NR5R6, and —NHC(O)R1; m is 2 to 5; and n is 0 to
 5. 2. A compoundaccording to claim 1 selected from the group consisting of:2-[4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide;2-[(3R,4R)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide;and2-[(3S,4S)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl]-N-hydroxyacetamide.3. A method of treating a bacterial infection by administering to asubject in need of treatment a compound according to claim 1.